1. Field of the Invention
The present invention relates to a tool holder, and more particularly a rotary tool holder for holding a rotating tool.
2. Description of Related Art
The known conventional rotary tool holder for holding rotating tools, which is installed on the spindle shaft of a machine tool, is a single-piece construction consisting of a tapered area c that contacts the inside peripheral surface b of a tapered hole in a spindle shaft a, an outer armor d at the top end of said spindle shaft a, and a tool attaching area e at the top end of the outer armor d, as shown in FIG. 8.
The conventional rotary tool holder as described above has the problem that a minute gap is created between the front end f of the spindle shaft a and the base end g of the outer armor d. Furthermore, even if the accuracy in the dimensions is improved in order to ensure that the front end f of the spindle shaft a comes into contact with the base end g of the outer armor d, it is difficult to maintain full contact between the components due to tolerances. For this reason, the installation accuracy of the rotary tool holder on the spindle shaft a is low, which makes the rotary tool holder unable to perform extremely precise cutting work required under conditions of high rotation speed and rapid workpiece feeding.